#include <stdio.h>
int Factorial(int num){
	if(num <= 1){
		return 1;
	}
	return num*Factorial(num-1);
}
int main(){
	int num = 0,ans = 0;
	scanf("%d",&num);
	ans = Factorial(num);
	printf("%d",ans);
	return 0; 
}

